The Property Research Of Optical Nanoantenna Based On The Surface Plasmons

In recent years, with the rapid development of nanotechnology, integrated optical device shows a continued evolution trend of integration and miniaturization, but due to the existence of the optical diffraction limitation, severely limits the integrated optical devices. The presence of surface plasmon in nano metallic structure can break through the diffraction limitation, therefore it has a broad application prospect in the study of optical devices. The arrival of the information era, electronic information technology exposed its limitations in the face of the vast amount of information, the emergence of photonic information technology can solve this difficult problem perfectly, this technology has many advantages, such as large transmission capacity, fast response speed, high processing speed and so on. In this field, the optics of surface plasmon is a hot research topic.Optical nanoantenna is an important research target in the field of nano metallic structure, it has the advantage of traditional radio frequencies and microwave antenna, and exists localized surface plasmon resonance effects and strong near-field coupling characteristics. At the same time optical nanoantenna can realize optics photons information transmission in integrated optical device. Nowadays, optical nanoantenna has widely application in the fields of the quantum information technology, high density data storage, optical and biological sensors. So designing optical nanoantenna with perfect far-field proprieties has a high research value.In this paper, we discussed the far-field characteristics of optical nanoantenna, most of all we make an intensive study of Yagi-Uda antenna and backfire antenna in nanometer size.According to the design theory of traditional antenna and the optical characteristics of nano metallic structure, we adjusted the structure model and size parameters of antenna elements, our aim is to design optical nanoantenna with different structure, afterwards we built, simulated and modeled the corresponding antenna models, then calculated and compared the far-field radiation characteristics of antenna, so as to design the optical nanoantenna with the superior performance.This paper studied the far field properties of nano-optical Yagi-Uda antenna firstly. On this basis, nano-optical backfire antenna simulation model was established. In this paper, we mainly studied the two important parameters of the antenna:antenna gain and the width of main lobe. Through the comparison and analysis the radiation characteristics of above two kind of antenna, we came to a conclusion that backfire antenna has superior directional properties compared with Yagi-Uda antenna, that is to say, antenna performance is greatly improved.Next, in this paper, we made a simulation analysis on the advanced backfire antenna. By changing the structure or size of antenna elements, finally the antenna with superior performance was designed. We proposed two kinds of design scheme, the first is to increase the focusing of electromagnetic wave in the main reflector, such as adding metal structure on the edge of the main reflector, or replacing the metal disk with sphere; the second is to change the nanorod elements of backfire antenna into cross or discal elements. Through the simulation calculation, we learned that these advanced backfire antennas’performance has been greatly enhanced.To sum up, through the appropriate of adjustments, we has designed optical nanoantennas with superior performance. The research work what we studied will provide important theoretical guidance value for antenna design.